Objectives. To evaluate the long-term success of antegrade collagen injection in men with stress urinary incontinence after radical prostatectomy. Methods. Between October 1994 and January 1996, 20 patients underwent antegrade collagen injection for stress urinary incontinence caused by radical prostatectomy. Evaluation by pad test, urodynamics, and subjective scores was performed before and after injection. Results. At a mean follow- up of 28 months, 10% of the patients were cured and 35% were improved. All patients received a single treatment (mean total volume of collagen injected 14.5 mL). In 11 patients without long-term improvement, 2 had undergone irradiation previously and 7 had failed retrograde collagen injections. Two patients with vesical neck contracture were successfully treated. Preoperative incontinence severity and stress leak point pressure did not correlate with failure. Conclusions. A 45% cured or improved rate at long- term follow-up is possible in men with stress incontinence after radical prostatectomy using a single antegrade collagen injection. Although antegrade delivery of collagen for stress incontinence minimized short-term, technique- related failures, for a substantial number of patients therapy had failed at long-term follow-up.